Dry trees for cost effective solution with the Wellhead Barge: WHB Benjamin MAURIES SAIPEM PAU, FRANCE 5 7 APRIL 2016
Dry Tree Solution for Mild Environments Dry Tree solutions have been developed and mainly used in harsh offshore environments (North Sea, Gulf of Mexico). For mild environments (like Gulf of Guinea): Reduced hull motions resulting from mild Possibility to use a simple spread-moored barge: With a large central wellbay suited to support surface trees and perform all drilling operations, Barge-type standard construction insensitive to topsides weight, That can accommodate optimized, naturally ventilated and segregated topsides layout thanks to its wide deck. 95% of waves Hs < 4.5 m Tp < 16 s Hs < 2.5 m Tp < 11 s Wind
Typical Application Cases WHB full Process (+ FSO or export line) WHB + FPSO (or FPU) WHB satellite WHB full process + FSO WHB functions: Surface trees Drilling rig and utilities Risers from subsea trees Living quarter Full process WHB Standard export line to FSO or to shore FSO WHB + FPSO or FPU WHB functions Surface trees Drilling rig and utilities Living quarter Manifold and tests only Poly-phase export to FPSO / FPU through fluid transfer lines WHB CALM FPSO
WHB Concept Introduction Combination of field proven technologies: Drilling Rig Topsides Surface BOP Saipem 12000 drilling vessel Hull & mooring High Pressure risers Aircans Spread-moored FPU Hull & Topsides Wellbay area
General Overview Hull dimensions for a full processing WHB (Topsides weight: 18 000 tonnes) Length: 274 m Width: 60 m Comparison with Saipem 10 000: Height: 19 m Moonpool: 78 x 18 m Topsides Hull Living Quarter Utilities Drilling & Risers Process Segregation of operational zones High safety level Saipem 10 000: Length: 228 m Width: 42 m Height: 19 m Moonpool: 25 x 10 m
Key Technical Features A drilling and production floating unit Large Water depth range from 500m to 3,000m WD Number of slots in the wellbay from 6 to 36+ to integrate free standing top-tensioned drytree risers Utilities modules Drilling rig Process Modules Oil production from 50,000 bopd to 250,000 bopd+ Large topsides carrying capacity Living quarter Flexibility in rig selection From full drilling rig to completion and work over rig Purchased or leased Also configurable for Tender Assisted drilling Adaptability to different field architectures High pressure risers Safety and reliability Hull & moorings
Production Risers Description Principles & Arrangement Description: Self-standing risers (top tensioned by means of aircans) Integrated into wellbay in two parallel rows Field proven risers components widely used on SPAR s & TLP s Christmas tree Roller guiding system Surface Dry-tree Christmas tree Stiffener joint Guiding system Aircans (3 parts) Stiffener joint : Ensure the interface between the production riser and the riser guiding system Aircans : Design optimized for minimum SCF and longer fatigue life Non-integral design: pressure containing element is not the inner shell of aircans Rotations and vertical relative motions between the risers and the hull are unconstrained Riser strings Subsea connector Tapered joint & connector Flexjoint Mud line
Wellbay and Mudline Pattern Subsea pattern defined according to exclusion zone Lowering operations performed with the WHB at the centre of the subsea pattern Prevent clashing issues between risers in production and deployed riser Exclusion zone definition WHB offset (1.5 % of the WD) Deflection of the riser base during deployment Wellbay Drilling slot Drilling riser parking positions Maximal vessel offset during operations Well position at seafloor Well position at surface Maximal riser deflection due to current (free end)
Taking Advantage of a Barge Type Floater A barge-type hull of standard shipyard construction High carrying capacity and large deck space A moonpool as a drillship A spread moored barge with active mooring system as on Saipem s Scarabeo 8 drilling semisubmersible Machinery, consumables and process tanks integrated into the hull
Extensive model test campaign to check : Hydrodynamic Tests Campaign Global motions behavior of the barges Moonpool hydrodynamics without and with risers Risers integration in the wellbay Specific model tests for current/risers interactions: Confirmation of riser design regarding fluid/structure interactions Improved predicting tools for clearance and dynamic analyses
High Flexibility in Drilling Facilities Design Fixed drilling rig dissociated from other topsides functions (LQ, utilities and process) Drilling operations derived from those of deep offshore drilling vessels Fixed drilling rig at the centre of the wellbay Configurable with both permanent purchased/leased rig or Tender Assisted Surface BOP drilling (with mini-subsea BOP if required) Hydro pneumatic tensioners for the handling of the BOP and the drilling riser tensioning Surface BOP Suited also for direct access to subsea wells instead of or in addition to dry-trees Possibility to have significant expanded storage of drilling/ completion fluids Ability to have significant additional tubulars storage capacity LESS TIME REQUIRED TO DRILL A WELL CAPACITY TO DRILL TOP HOLE SECTIONS Saipem 10,000 Permanent rig
WHB Typical Execution Plan Small modules + Vendor packages Easy fabrication Limited lifting capacity required at integration yard Drilling facilities built and integrated in topsides fabrication yard (modular construction) Integration & commissionning at quay NO OFFSHORE LIFT & OFFSHORE HOOK UP Modules and buildings fabricated at the fabrication yard Procured skids and buildings Drilling rig substructure module Loosed equipment procured and installed directly on hull
Conclusions The WHB is a cost-effective, robust and flexible dry-tree solution for a field development in mild environments: CAPEX savings: A single drilling & production floater with: Standard barge-type hull construction High carrying capacity and large deck space Spread mooring Topside integration alongside quay, no offshore lift & no offshore hook-up DRILLEX OPEX savings: Drilling time savings thanks to permanent drilling riser installation with parking slots Possibility for simultaneous drilling/completion/work-over operations and production (with SIMOPS analysis) Marginal cost of work-over and infield drilling Higher oil recovery Faster intervention on wells Reduction of overall manning on site, all functions on the same vessel Innovative concept using fieldproven systems & procedures Flexibility in the field application case and the drilling facilities design
Thank you for your attention Contacts: benjamin.mauries@saipem.com stephanie.abrand@saipem.com paolo.allara@saipem.com